GB2211709A - Multileaf collimator and related apparatus - Google Patents

Multileaf collimator and related apparatus Download PDF

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Publication number
GB2211709A
GB2211709A GB8725253A GB8725253A GB2211709A GB 2211709 A GB2211709 A GB 2211709A GB 8725253 A GB8725253 A GB 8725253A GB 8725253 A GB8725253 A GB 8725253A GB 2211709 A GB2211709 A GB 2211709A
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Prior art keywords
members
retroreflector
positions
edges
leaves
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GB8725253A
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GB2211709B (en
GB8725253D0 (en
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Kevin John Brown
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Philips Electronics UK Ltd
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Philips Electronic and Associated Industries Ltd
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Priority to GB8725253A priority Critical patent/GB2211709B/en
Publication of GB8725253D0 publication Critical patent/GB8725253D0/en
Priority to DE88202298T priority patent/DE3882899T2/en
Priority to EP88202298A priority patent/EP0314231B1/en
Priority to JP63267321A priority patent/JP2644007B2/en
Priority to US07/263,090 priority patent/US4882741A/en
Publication of GB2211709A publication Critical patent/GB2211709A/en
Application granted granted Critical
Publication of GB2211709B publication Critical patent/GB2211709B/en
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • A61N5/1042—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy with spatial modulation of the radiation beam within the treatment head
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • A61N5/1042—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy with spatial modulation of the radiation beam within the treatment head
    • A61N5/1045—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy with spatial modulation of the radiation beam within the treatment head using a multi-leaf collimator, e.g. for intensity modulated radiation therapy or IMRT
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • A61N5/1048—Monitoring, verifying, controlling systems and methods
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
    • G21K1/00—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating
    • G21K1/02—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators
    • G21K1/04—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators using variable diaphragms, shutters, choppers
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
    • G21K1/00—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating
    • G21K1/02—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators
    • G21K1/04—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators using variable diaphragms, shutters, choppers
    • G21K1/046—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators using variable diaphragms, shutters, choppers varying the contour of the field, e.g. multileaf collimators
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B90/00—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
    • A61B90/36—Image-producing devices or illumination devices not otherwise provided for
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B90/00—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
    • A61B90/90—Identification means for patients or instruments, e.g. tags
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • A61N5/1048—Monitoring, verifying, controlling systems and methods
    • A61N5/1049—Monitoring, verifying, controlling systems and methods for verifying the position of the patient with respect to the radiation beam
    • A61N2005/1059—Monitoring, verifying, controlling systems and methods for verifying the position of the patient with respect to the radiation beam using cameras imaging the patient
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • A61N2005/1085—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy characterised by the type of particles applied to the patient
    • A61N2005/1089—Electrons

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  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Physics & Mathematics (AREA)
  • General Health & Medical Sciences (AREA)
  • Radiology & Medical Imaging (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Pathology (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Radiation-Therapy Devices (AREA)
  • Apparatus For Radiation Diagnosis (AREA)

Description

1 PHS 33Z711709 MULTILEAF COLLIMATOR AND RELATED APPARATUS The invention
relates to a collimating arrangement for a beam of radiation, comprising a set of mutually contiguous members which substantially attenuate said radiation, the positions of the members being adjustable so that edges thereof form an adjustable aperture for defining the cross-sectional shape of the beam, the arrangement including illuminating means to illuminate said aperture and optical detecting means responsive to spatial variations generally across the aperture in the intensity of illumination reaching the detecting means to determine the positions of said edges, the arrangement being such that the illuminating means and detecting means are at locations optically substantially corresponding to the source of said beam.
The invention further relates to radiotherapy apparatus comprising such a collimating arrangement.
A collimating arrangement as set forth in the opening paragraph is known from EP 193 509 A. The specification discloses a multileaf collimator, particularly for radiation therapy equipment using a high-energy beam of penetrating radiation, with an optical system comprising a light bulb to illuminate the irradiated surface, mirrors, and a TV camera which is arranged to "see" the leaf collimator from the effective radiation source. The TV camera estabishes the position of each collimator leaf by detecting light/dark transitions in predetermined lines of the TV camera picture. In the arrangement described in detail with reference to Figure 8 of the drawings which depicts a pair of opposite leaves as seen by the TV camera, the leaves appear to be dark and the region between the leaves, which forms part of the aperture defining the area to be irradiated by the high-energy beam, appears to be light. This has the disadvantage that the intensity of illumination seen by the TV camera in the region between the leaves will depend inter alia on the reflectivity of the surface to be irradiated, and consequently that the contrast between the light an dark areas is variable and is in practice 2 PHB 33394 liable to be rather poor; as a result, the determination of the positions of the edges of the leaves may not be reliably accurate. The specification mentions alternatives to the arrangement described in detail, including providing the upper surface of the leaves with a reflective surface reflecting the field light back into the TV camera; it is not clear from the specification how exactly this alternative arrangement would operate, but it would also be liable to variable and rather poor contrast.
According to the present invention, a collimating arrangement as set forth in the opening paragraph of this specification is characterised in that respective retroreflector means are coupled to each of said members so that the positions of the retroreflector means are respectively representative of the positions of said edges.. the retroreflector means being arranged to reflect illumination from the illuminating means into the detecting means and the detecting means being responsive to the higher intensity of illumination from the retroreflector means than from respectively adjacent regions for determining the positions of said edges. Such an arrangement has the advantage over the above-mentioned known arrangement of enabling a much higher level of contrast to be obtained, so that the determination of the positions of the edges of the members can be substantially independent of factors such as the reflectivity of the surface to be irradiated and the intensity of ambient illumination.
Each of the retroreflector means, which may for example be a strip of commercially-available retroreflective material, may extend along the respective leaf, i.e. in a direction transverse to the beam-defining edge of the leaf, for most or all of its length so that the detecting means only "see" one edge of the retroreflector means. Suitably however, each of the retroreflector means has a limited extent in a direction transverse to the respective beam- defining edge and the detecting means are responsive to the spatial variations in the intensity of illumination at opposite edges of each retroreflector means in said direction to determine an average position in said direction of the 3 PHB 33394 retroreflector means and hence of the respective beam-defining edge. Where the detecting means are operable to determine the position of the beam-defining edge from the position at which the intensity of illumination (at the edge of the retroreflector means) passes through a predetermined threshold. the determined position is thus substantially independent of variations in the intensity of illumination due for example to ageing or to variations in a supply voltage.
A collimator embodying the invention may be used in radiotherapy apparatus comprising means for generating a beam of penetrating radiation, in that case high-energy X-rays or electrons. As an alternative, a collimating arrangement embodying the invention may be used with diagnostic apparatus, for example an X-ray simulator which is intended for use in conjunction with radiotherapy apparatus and which comprises a patient support table and a source of diagnostic X-rays at a position corresponding to the source of high-energy radiation in the radiotherapy apparatus.
In such radiotherapy apparatus, the detecting means may also be operable to determine a desired cross-sectional beam shape defined by retroreflector means other than on said members, the other retroreflector means also being illuminated by the illuminating means, and wherein the apparatus comprises means for storing said desired shape and means for adjusting the positions of said members so that the actual beam shape substantially corresponds to the desired shape. This can be used for setting the aparatus so as to illuminate a desired region of a patient. There may for example be provided a corresponding set of mutually contiguous further members which substantially attenuate the illumination from the illuminating means, the positions of the further members being adjustable and the set of further members being arrangeable so that edges of the further members form an adjustable aperture defining the cross-sectional shape of the illuminating beam from the illuminating means, the lengths of said edges respectively subtending the same angles at the illuminating means as the lengths of corresponding edges of the members of the 4 PHB 33394 first-said set respectively subtend at said source, wherein respective further retroreflector means are coupled to each of said further members so that the positions of the further retroreflector means are respectively representative of the positions of the edges of the further members, the further retroreflector means being arranged to reflect illumination from the illuminating means into the detecting means. With the patient positioned for treatment, the further (illumination-attentuating) members may be adjusted so that the boundary of the illuminated area on the patient substantially matches an outline drawn on the skin of the patient.
The apparent positions of the edges of the further members, i.e. in terms of the angles subtended at the illuminating means, can then be stored and the main set of radiation-attenuating members set to the same positions. As an alternative, there may be provided retroreflector means and support means therefor adapted to be manually moved along a path defining the desired beam shape, for example retroreflector means mounted at the end of a stick.
Embodiments of the invention will now be described, by way of example, with reference to the schematic drawings, in which:
Figure 1 is a side view showing in outline radiotherapy apparatus comprising a collimating arrangement embodying the invention; Figure 2 is a plan view of a multileaf collimator defining the cross-sectional shape of the high-energy beam of radiation; Figure 3 is a side view of the optical system for determining the positions of the edges of the leaves and a pair of the leaves, and Figure 4 is a graph of illumination intensity against distance.
Figure 1 illustrates apparatus for irradiating a patient with a beam of high-energy electrons or X-rays. The patient is supported on an adjustable table 1. A gantry 2 rotatable through substantially 3600 about a horizontal axis 3 supports an electron source 4, a linear accelerator (Linac) 5 which accelerates the electro;s to a selectable energy typically in the range 4-25 MeV, a PHB 33394 beam-deflection system at 6 which gives the electron beam a net deflection of more than 90 degrees so that the beam is directed normally towards the axis 3, and a head 7 which comprises means for providing the radiotherapy beam with the desired characteristics and which includes a collimating arrangement embodying the invention. The radiotherapy beam may be the electron beam produced by the linac or may be a beam of high-energy X-rays produced by causing the electron beam to impinge, after deflection at 6, on a suitable X-ray target.
Figure 2 is a plan view of a multileaf collimator in the head 7, and Figure 3 is a side view of the optical system for determining the positions of the edges of the leaves together with one pair of leaves, Figure 2 being a view from the side of the collimator facing the incident beam, i.e. from above with respect to the orientation depicted in Figures 1 and 3. The collimator comprises a set of parallel mutually contiguous elongate members, some of which are designated 8, arranged as pairs of longitudinally opposed leaves. The positions of the leaves are rectilinearly adjustable longitudinally, that is to say in the x-direction indicated in Figure 2, by means not shown (such as respective electric motors). The material of the leaves and their thickness (their dimension in the z-direction indicated in Figure 3) are such that they substantially attenuate the portion of the beam of highenergy radiation that is incident on them. The edge of each leaf nearest the longitudinally opposed leaf of the same pair forms a portion of an aperture 9 for defining the cross-sectional shape of the beam. The leaves are sufficiently narrow (their y-dimension) and sufficiently numerous to enable the cross-sectional beam shape to be closely approximated to a desired region to be irradiated on a patient.
Referring particularly to Figure 3, the location of the effective source of the radiation beam is designated 10. This location is the point at which the deflected beam of electrons derived from the linac is brought to a focus (suitably a focus with respect to both position and velocity); if the radiotherapy beam is 6 PHB 33394 to be of X-rays rather than electrons, a suitable X-ray target is disposed at that location. The distance from the source of the collimator leaves is designated D, and the distance from the source of the region of the patient to be irradiated (for simplicity indicated as a surface 11) is designated D2. An optical system for determining the positions of the edges of the leaves that bound the aperture 9 comprises an illuminating lamp 12, a video camera 13, a semi- transparent mirror 14 and a mirror 15 which is reflective to the illumination from the lamp 12 and which either is substantially transparent to the beam of high-energy radiation or can be moved out of the path of the radiation beam when the latter is in use. The arrangement is such that the lamp 12 and camera 13 are at locations optically substantially corresponding to one another and also to the effective source 10 of the radiation beam. An optically black surface 16 is disposed directly in front of the camera 13 beyond the semi-transparent mirror 14. The camera 13 is connected to video processing and storage means 17, which in turn are connected to control means 18 for adjusting the positions of the Leaves 8.
As so far described, the optical system resembles that disclosed in the above-mentioned EP 193 509 A. However, to obtain much greater contrast for determining the positions of the edges of the leaves, each of the leaves has respective retrorefLector means 19 mounted on its narrow upper Longitudinal side facing the illuminating beam. As a result, Light from the Lamp 12 which is incident on the retrorefLectors is reflected back substantially along its incident path, irrespective of the positions of the Leaves, and approximately half this reflected illumination is directed to the camera 13. Consequently, the camera "sees" a much higher Level of illumination from the retroreflectors than from the adjacent regions in its field of viewo the latter being Light from the lamp 12 reflected or scattered from the upper sides of the leaves and Light from the lamp 12 plus ambient illumination scattered from the surface 11. The retroreflectors can thus be unambiguously discerned against the background.
7 PHB 33394 In this embodiment, the retroreflectors have a limited extent in a direction transverse to the beam-defining edges of the leaves, i.e. the x- direction. The variation with distance in the x-direction of the intensity I of illumination reaching the camera from the vicinity of a retroreflector is indicated diagrammatically in Figure 4 for two different levels of illumination from the lamp, giving maximum intensities I, and 12 respectively from the retroreflector. The processing and storage means 17 determine the positions at which the intensity crosses a threshold value ITO namely xAl xB with the higher level of illumination and xC, xD with the lower level; it then determines the mean or mid-point position xM. As is apparent from Figure 4, the value of xM is independent of the level of illumination. The system is calibrated prior to use so as to derive from xM the position of the respective beam-defining edge. The retroreflector means may accordingly be positioned at any convenient location along the upper side of the leaf so as to reflect illumination from the lamp 12 into the camera 13.
As an alternative to the localised retroreflector means just described, the retroreflector means may extend along most or all of a leaf so that only one edge (extending in the y-direction) of the retroreflector means is visible to the camera. In that case, however, the apparent position of the edge of the retroreflector is liable to vary with the level of illumination from the lamp.
The camera and the processing and storage means may also be operable to determine a desired cross-sectional shape for the radiation beam defined by retroreflectors other than on the leaves. Figure 3 illustrates two different ways in which this can be achieved. In the first, a further set of mutually contiguous leaves is fitted in the head 7 (Figure 1); two opposed leaves are indicated at 20 in Figure 3. This further set of leaves is analogous to the main collimator for the radiation beam except that the further leaves are required only substantially to attenuate the illumination (in practice, they are likely to have negligible transmission for the illumination) and that, being at a distance D3 8 PHS 33394 from the effective source of the radiation beam that is greater than the distance D1 of the main collimator from the source, the leaves 20 are of greater width (their dimension in the y-direction) so that they subtend the same angles at the source as the leaves 8J.
i.e. the respective widths are in the ration D3/D1. When the further set of leaves is to be used (the further set may be removably fitted in the head 7), the leaves of the main collimator are adjusted to provide the maximum aperture so that the cross-sectional shape of the illuminating beam is defined by the further set. The positions of the further leaves can be manually adjusted so that the boundary of the illuminated area on the surface 11 substantially matches an outline which is, for example. drawn on the skin of the patient. Each of the further leaves carries respective further retroreflector means 21 whereby the positions of the edges of the further leaves can be determined by the camera 13 and the processing and storage means 17 in the same manner as with the main collimator. the positions then being stored at 17. The further set of leaves is then opened to provide its maximum aperture or is completely removed from the head 7., and the stored edge positions are supplied to the control means 18 so that the edges of the leaves 8 of the main collimator are adjusted to the same respective apparent positions as the leaves 20: the desired region on the surface 11 will then be irradiated. since the transverse dimensions of the two sets of leaves subtend substantially the same respective angles at the source 10 (with reference. for example. to a central axis normal to the surface 11).
An alternative manner of determining the desired cross-sectional beam shape is simply to use a stick 22 carrying retroreflector means 23 at its tip: the tip is manually traced along the outline of the area which it is desired to irradiate.
For both the radiation-attenuating main collimator and the illuminationattenuating further collimator, it is not essential that the retroreflector means should be mounted directly on the 1, leaves but only that the retroreflector means should be coupled to 9 PHB 33394 the leaves so that the positions of the retroreflector means are respectively representative of the positions of the edges of the leaves; the retroreflector mean may for example be coupled to the leaves by respective levers.
As mentioned above, a collimating arrangement embodying the invention may also be used wih diagnostic X-rays rather than a beam of high-energy therapeutic radiation, typically in an X-ray simulator intended for use in conjunction with radiotherapy apparatus. Such a simulator is constructed to be analogous to the radiotherapy apparatus but to have a source of diagnostic X-rays at a location corresponding to the effective source of the high-energy beam. The simulator comprises an image-converting screen and video camera whereby the X-ray image of a portion of a patient can be displayed on a video screen. The leaves of the collimator can be adjusted so that the desired region of the patient is irradiated by the X-rays, and the positions of the edges of the leaves determined by the optical system. This information can then be fed to the radiotherapy apparatus so that the same region of the patient will be irradiated by the high-energy beam. 20 The retroreflector means used in embodiments of the invention may for example be individual corner cubes or may be portions of a commercially-available strip of retroreflective material such as "SCOTCHLITV' available in the UK from 3M UK PLC. While the invention has been described with reference to a collimating arrangement forming part of apparatus for radiotherapy or for diagnostic or simulation using conventional fluoroscopy, it may equally well be correspondingly employed in irradiation apparatus employed for other purposes such as for industrial or manufacturing use. From reading the present disclosure, other modifications will be apparent to persons skilled in the art. Such modifications may involve other features which are already known in the design, manufacture and use of radiotherapy apparatus and collimating arrangements and component parts thereof and which may be used instead of or in addition to features already described herein.
PHB 33394 Although claims have been formulated in this application to particular combinations of features, it should be understood that the scope of the disclosure of the present application also includes any novel feature or any novel combination of features disclosed.herein either explicitly or implicitly or any generalisation thereof, whether or not it relates to the same invention as presently claimed in any claim and whether or not it mitigates any or all of the same technical problems as does the present invention. The applicants hereby give notice that new claims may be formulated to such features andlor combinations of such features during the prosecution of the present application or of any further application derived therefrom.
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Claims (1)

  1. 5. Apparatus as claimed in Claim 4 wherein the detecting means are
    operable to determine a desired cross-sectional beam shape defined by retroreflector means other than on said members, the other retroreflector means also being illuminated by the illuminating means, and wherein the apparatus comprises means for storing said desired shape and means for adjusting the positions of said members so that the actual beam shape substantially corresponds to the desired shape.
    6. Apparatus as claimed in Claim 5 in combination with a corresponding set of mutually contiguous further members which substantially attenuate the illumination from the illuminating means, the positions of the further members being adjustable and the set of further members being arrangeable so that edges of the further members form an adjustable aperture defining the cross-sectional shape of the illuminating beam from the illuminating means, the lengths of said edges respectively subtending the same angles at the illuminating means as the Lengths of corresponding edges of the members of the first-said set respectively subtend at said source, wherein respective further retroreflector means are coupled to each of said further members so that the positions of the further retroreflector means are respectively representative of the positions of the edges of the further members, the further retrore flector means being arranged to reflect illumination from the illuminating means into the detecting 25 means.
    7. Apparatus as claimed in Claim 5 in combination with retroreflector means and support means therefor adapted to be manually moved along a path defining the desired beam shape.
    8. Radiotherapy apparatus comprising irradiation apparatus 30 as claimed in any one of Claims 4 to 7.
    9. Radiotherapy apparatus substantially as herein described with reference to the accompanying drawings.
    Published 1989 atThe Patent Office. State House, 66,71 High Holburn,Lon. :icr'WGJR 4TP. Further copiesmaybe obtained from The Patent Ofoce. Sales Branch. St Mary cray, orpulgton. Kent BP5 3RD. Printed by multiplex techniques ltd. St Mary Cray, Kent, Con. 1187
GB8725253A 1987-10-28 1987-10-28 Multileaf collimator and related apparatus Expired - Lifetime GB2211709B (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
GB8725253A GB2211709B (en) 1987-10-28 1987-10-28 Multileaf collimator and related apparatus
DE88202298T DE3882899T2 (en) 1987-10-28 1988-10-14 Multi-layer collimator and device using the same.
EP88202298A EP0314231B1 (en) 1987-10-28 1988-10-14 Multileaf collimator and related apparatus
JP63267321A JP2644007B2 (en) 1987-10-28 1988-10-25 Collimator for radiation beam
US07/263,090 US4882741A (en) 1987-10-28 1988-10-26 Multileaf collimator and related apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB8725253A GB2211709B (en) 1987-10-28 1987-10-28 Multileaf collimator and related apparatus

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GB8725253D0 GB8725253D0 (en) 1987-12-02
GB2211709A true GB2211709A (en) 1989-07-05
GB2211709B GB2211709B (en) 1991-03-20

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JP (1) JP2644007B2 (en)
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2317545A (en) * 1996-08-16 1998-03-25 Siemens Medical Systems Inc System for aligning a radiation beam for radiation therapy
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Families Citing this family (58)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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US5757881A (en) * 1997-01-06 1998-05-26 Siemens Business Communication Systems, Inc. Redundant field-defining arrays for a radiation system
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US6052430A (en) * 1997-09-25 2000-04-18 Siemens Medical Systems, Inc. Dynamic sub-space intensity modulation
US6167114A (en) * 1998-08-10 2000-12-26 Siemens Medical Systems, Inc. System and method for calculating scatter radiation including a collimator thickness
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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0193509A2 (en) * 1985-02-28 1986-09-03 Instrument Ab Scanditronix Multi leaf collimator

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4754147A (en) * 1986-04-11 1988-06-28 Michigan State University Variable radiation collimator
US4739173A (en) * 1986-04-11 1988-04-19 Board Of Trustees Operating Michigan State University Collimator apparatus and method

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0193509A2 (en) * 1985-02-28 1986-09-03 Instrument Ab Scanditronix Multi leaf collimator

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2317545A (en) * 1996-08-16 1998-03-25 Siemens Medical Systems Inc System for aligning a radiation beam for radiation therapy
GB2341301A (en) * 1998-08-28 2000-03-08 Elekta Ab Collimator for radiotherapy apparatus
GB2341301B (en) * 1998-08-28 2003-04-09 Elekta Ab Collimator for radiotherapy apparatus
GB2457072A (en) * 2008-02-01 2009-08-05 Elekta Ab Fluorescence vision system
US10576301B2 (en) 2008-02-01 2020-03-03 Elekta Ab (Publ) Machine vision system

Also Published As

Publication number Publication date
GB2211709B (en) 1991-03-20
GB8725253D0 (en) 1987-12-02
JPH01146564A (en) 1989-06-08
EP0314231A2 (en) 1989-05-03
EP0314231A3 (en) 1990-02-07
DE3882899D1 (en) 1993-09-09
JP2644007B2 (en) 1997-08-25
DE3882899T2 (en) 1994-03-31
US4882741A (en) 1989-11-21
EP0314231B1 (en) 1993-08-04

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